MM: Satellites Propelled With Water; Spit Activated Battery

In this Manufacturing Minute episode, propelling satellites with teaspoons of water and a spit activated battery

Water Propulsion For Satellites

CubeStas are small, inexpensive satellites great for certain data gathering missions, but their simple design also limits their uses. One glaring omission is their own propulsion systems. But now a team of researchers at Purdue University have addressed that issue with water.

The Purdue team has developed a system that will allow the compact satellites to propel themselves in space by spraying jets of water. The prototype was 10cm cubed and weighed 6 lbs full of electronic components normally used for IoT devices.

The propulsion system, dubbed a Film-Evaporation MEMS Tunable Array thruster, uses about a teaspoon of ultra-purified water. The tank includes capillaries about 10 microns wide that hold the water in thanks to surface tension. Small heaters around the holes can be activated on demand to warm the water into vapor to create tiny blasts with a thrust-to-power ration of 230 micronewtons per watt for each 80 second spray.

While the prototype currently uses 4 thrusters, a CubeSat in orbit would need a full set of 12 thrusters. Researchers presented their finding a recent AIAA/USU Conference on small satellites.


Is this an ingenious way to propel small satellites into the unknown? Tell us what you think by leaving your comments below.

Spit Activated Battery

Researchers at Binghamton University have created a microbial fuel cell battery that is activated by spit.

The high-performance, paper-based, bacteria powered battery is created by constructing fuel cells from inactive, freeze-dried exoelectrogenic cells. Once saliva is added, the cells generate power within minutes.

Because the device uses freeze-dried cells, it can be stored for long periods of time without degradation. In testing, researchers were able to achieve a few microwatts of power per square centimeter — enough to power an LED light.

Because spit is readily available basically everywhere, the team hopes the device could eventually be used to power disposable diagnostic devices in developing countries or resource-constrained areas.


Do you think bacteria-powered batteries could be a reliable alternative energy source? In what other applications do you think this technology would be useful? Let us know what you think in the comments below.

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